About 2 weeks ago I changed the oil in my dad's '91 S10 for him. It has the 4.3L V6. I had 2 1/2 quarts of M1 10w30 (SL) and 2 quarts of Mobil dino (SJ). Dumped them in and all was well for up until yesterday.
This engine has never made any odd noises before. It had bad valve guides which were repaired about 6 months ago. Yesterday was the first day since the oil change to M1/Mdino that the truck was run for a long period of time on the oil. It was driven for about 120mi consisting of trips of about 30mi each. In between which it sat for about 20mi while my father did his water sampling at the small town drinking water plants he oversees.
On the final return leg of the trip he noticed when stopping and idling that there was a lot of what sounded like valvetrain noise... a lot of ticking/clacking.
Mind you, this engine has never made any noise at all in the past. So perhaps its the case that M1 is just too thin for some engines. Whatever it is this is the 4th GM engine that I've experienced an increase in what seems to be valvetrain noise when using Mobil1. The other engines were a 3.8L with over 100K mi, a 3.1L with ~45K mi, and a 3.1L with less than 15K mi on it.
In the case of the 3.8L switching to Havoline syn 10w30 completely eliminated any ticking/clacking that I had for the year and a half while using M1. The same goes for the Havoline 10w30 HiMileage in it right now.
On the 3.1L with less that 15K mi, I initially filled it with 5w30 Havoline dino. No tick/clack. On the next two oil changes I used 5w30 M1. Very noticeable tick/clack at idle. Switching to Havoline syn 5w30 or the Havoilne semi-syn 10w30 that is in it right now produces no tick/clack.
On the 3.1L with ~45K mi. I sold it while still running M1 5w30 (10w30 in summer). It had a very loud tick/clack at idle... Prior to using the M1 I used Valvoline 5 and 10w30 up till 20K mi. No valvetrain noise at all until switching to M1.
This doesn't make sense, since the Havoline syns have approx. the same cSt@100degF as M1 (both right about 10.1) and yet the Havoline produces no noise. And with the Mobil1 there was noise not just when the engine was hot/oil up to temp. The tick/clack occurred at idle whether the engine was cool or had been run for 2 hours. The Havoline produces no noise either at cold start or in a hot engine at idle.
I don't think I'll ever go back to using M1 in any vehicle ever again. It may be an excellent oil, but something seems a bit fishy when I see the same results (tick/clack) in 4 different engines of 3 different displacements.
[ May 14, 2004, 02:02 PM: Message edited by: Forkman ]
This engine has never made any odd noises before. It had bad valve guides which were repaired about 6 months ago. Yesterday was the first day since the oil change to M1/Mdino that the truck was run for a long period of time on the oil. It was driven for about 120mi consisting of trips of about 30mi each. In between which it sat for about 20mi while my father did his water sampling at the small town drinking water plants he oversees.
On the final return leg of the trip he noticed when stopping and idling that there was a lot of what sounded like valvetrain noise... a lot of ticking/clacking.
Mind you, this engine has never made any noise at all in the past. So perhaps its the case that M1 is just too thin for some engines. Whatever it is this is the 4th GM engine that I've experienced an increase in what seems to be valvetrain noise when using Mobil1. The other engines were a 3.8L with over 100K mi, a 3.1L with ~45K mi, and a 3.1L with less than 15K mi on it.
In the case of the 3.8L switching to Havoline syn 10w30 completely eliminated any ticking/clacking that I had for the year and a half while using M1. The same goes for the Havoline 10w30 HiMileage in it right now.
On the 3.1L with less that 15K mi, I initially filled it with 5w30 Havoline dino. No tick/clack. On the next two oil changes I used 5w30 M1. Very noticeable tick/clack at idle. Switching to Havoline syn 5w30 or the Havoilne semi-syn 10w30 that is in it right now produces no tick/clack.
On the 3.1L with ~45K mi. I sold it while still running M1 5w30 (10w30 in summer). It had a very loud tick/clack at idle... Prior to using the M1 I used Valvoline 5 and 10w30 up till 20K mi. No valvetrain noise at all until switching to M1.
This doesn't make sense, since the Havoline syns have approx. the same cSt@100degF as M1 (both right about 10.1) and yet the Havoline produces no noise. And with the Mobil1 there was noise not just when the engine was hot/oil up to temp. The tick/clack occurred at idle whether the engine was cool or had been run for 2 hours. The Havoline produces no noise either at cold start or in a hot engine at idle.
I don't think I'll ever go back to using M1 in any vehicle ever again. It may be an excellent oil, but something seems a bit fishy when I see the same results (tick/clack) in 4 different engines of 3 different displacements.
[ May 14, 2004, 02:02 PM: Message edited by: Forkman ]
